man/man9f/get_pktiopb.9f

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 GET_PKTIOPB 9F "Jan 16, 2006"
 NAME
get_pktiopb, free_pktiopb - allocate/free a SCSI packet in the iopb map
 SYNOPSIS

#include <sys/scsi/scsi.h>


struct scsi_pkt *get_pktiopb(struct scsi_address *ap,
 caddr_t *datap, int cdblen, int statuslen, int datalen,
 int readflag, int (*callback);


void free_pktiopb(struct scsi_pkt *pkt, caddr_t datap, int datalen);


 INTERFACE LEVEL

These interfaces are obsolete. Use scsi_alloc_consistent_buf(9F) instead
of get_pktiopb(). Use scsi_free_consistent_buf(9F) instead of
free_pktiopb().
 PARAMETERS
ap

Pointer to the target's scsi_address structure.


datap

Pointer to the address of the packet, set by this function.


cdblen

Number of bytes required for the SCSI command descriptor block (CDB).


statuslen

Number of bytes required for the SCSI status area.


datalen

Number of bytes required for the data area of the SCSI command.


readflag

If non-zero, data will be transferred from the SCSI target.


callback

Pointer to a callback function, or NULL_FUNC or SLEEP_FUNC


pkt

Pointer to a scsi_pkt(9S) structure.


 DESCRIPTION

The get_pktiopb() function allocates a scsi_pkt structure that has
a small data area allocated. It is used by some SCSI commands such as
REQUEST_SENSE, which involve a small amount of data and require
cache-consistent memory for proper operation. It uses ddi_iopb_alloc(9F)
for allocating the data area and scsi_resalloc(9F) to allocate the packet
and DMA resources.

callback indicates what get_pktiopb() should do when resources are
not available:
NULL_FUNC

Do not wait for resources. Return a NULL pointer.


SLEEP_FUNC

Wait indefinitely for resources.


Other Values

callback points to a function which is called when resources may have
become available. callback must return either 0 (indicating
that it attempted to allocate resources but failed to do so again), in which
case it is put back on a list to be called again later, or 1 indicating
either success in allocating resources or indicating that it no longer cares
for a retry.


The free_pktiopb() function is used for freeing the packet and its
associated resources.
 RETURN VALUES

The get_pktiopb() function returns a pointer to the newly allocated
scsi_pkt or a NULL pointer.
 CONTEXT

If callback is SLEEP_FUNC, then this routine can be called only
from user or kernel context. Otherwise, it can be called from user, interrupt,
or kernel context. The callback function should not block or call
routines that block.

The free_pktiopb() function can be called from user, interrupt, or kernel
context.
 ATTRIBUTES

See attributes(5) for a description of the following attributes:


ATTRIBUTE TYPE ATTRIBUTE VALUE
Stability Level Obsolete


 SEE ALSO

attributes(5), ddi_iopb_alloc(9F),
scsi_alloc_consistent_buf(9F), scsi_free_consistent_buf(9F),
scsi_pktalloc(9F), scsi_resalloc(9F), scsi_pkt(9S)

Writing Device Drivers
 NOTES

The get_pktiopb() and free_pktiopb() functions are obsolete and
will be discontinued in a future release. These functions have been replaced
by, respectively, scsi_alloc_consistent_buf(9F) and
scsi_free_consistent_buf(9F).

The get_pktiopb() function uses scarce resources. For this reason and its
obsolescence (see above), its use is discouraged.